The present invention relates to sample handling in an automated diagnostic analyzer. In particular, the present invention relates to two dimensional sample handling in an automated diagnostic analyzers to allow greater access to a larger number of samples.
Known diagnostic analyzers include immunodiagnostic analyzers such as the Vitros® ECi immunodiagnostic analyzer, or clinical chemistry analyzers such as the Vitros® 5,1 FS, both sold by Ortho-Clinical Diagnostics, Inc. All such analyzers are collectively called diagnostic analyzers. Representative systems are disclosed for example in U.S. Published Patent Application No. 2003/0026733 and in U.S. application Ser. No. 10/684,599 filed Oct. 14, 2003, both of which are incorporated herein by reference in their entireties. Such systems have sample handling systems. For example, in the '733 publication a sample handler 14 has sample trays 18 (also called sample carriers), which contain individual sample containers, such as test tubes. The sample handler transports the sample trays on a belt (not shown) under metering transport rail 26 along a straight path, where metering truck 30 containing a sample aspirate/dispense probe will aspirate sample out of the individual sample containers. The sample trays 18 are shown in more detail in FIG. 3 of the '599 application. The sample tray (or sample carousel) 220 sits atop sample tray transport 210 which is either magnetically transported or is transported by a belt system in an elliptical path to a sample aspirate station 230 (see FIG. 1).
Both of these systems are constrained in that the metering probe can only access a single sample carousel at a time. This has the effect of slowing down the metering process. Also, it constrains the number of samples that can be accessed at single time. For example, if one carousel contains a sample being analyzed for HDL and another carousel also contains a sample also being analyzed for HDL only the first sample can be accessed. But, it would increase throughput to analyze both samples for HDL. However, for this to happen the sample transport would have to position the second carousel under the metering probe, hence slowing down the overall system speed.
One solution for accessing a greater number of sample carousels is to provide a metering probe that can move in two horizontal directions, thus allowing access to a greater number of sample trays and hence a greater number of samples. However, to ensure precise metering of sample, the sample and by definition the sample tray must be precisely registered in a predetermined position to ensure the metering probe will be able to properly access the sample container. In known systems, such as those described above, the sample tray is advanced past a fixed projection or registration stop. Once past, the sample tray is reversed and brought into a snug contact with the registration stop, thus providing proper registration. When more than one sample tray is to be registered, such as with the system shown in the '733 publication, i.e., one for the primary metering station and one for the reflex metering station, the trays are driven via the belt past their respective registration stops, the drive is then reversed and the trays registered against the registration stops. The flexibility of the direct drive belt, because of its length and distance from the drive pulley, insures both a proper loading tension and location for metering.
However, for systems requiring additional trays to be registered, the use of equivalent mechanical methods, such as the registration stop to register multiple sample trays simultaneously in more than one dimension would result in an over-constrained design (where the number of mechanical constraints would exceed the number of free parameters available). A system such as that described with respect to the '733 publication and the '599 application (i.e., registration is to be accomplished by reversing the drive direction and forcing the trays up against a registration stop), would require the tray transport to have a rigid coupling between trays and would subject the trays to higher than desired impact loads during registration.
Newer analyzer designs, such as shown in FIG. 1 employ multiple sample trays using a belt drive to move the trays from position to position where up to four of the sample trays can be registered at the same time. Given that the positional accuracy requirement of newer analyzers is the same as for analyzers known in the art, the use of equivalent mechanical methods to register four of the sample trays simultaneously would result in an over-constrained design (where the number of mechanical constraints would exceed the number of free parameters available). In a manner similar to the known analyzers, such as the ECi and 5,1FS analyzers described above, registration is to be accomplished by reversing the drive direction and forcing the trays up against a registration stop. This in turn would require the tray transport to have a rigid coupling between trays and would subject the trays to higher than desired impact loads during registration.
For the foregoing reasons, there is a need for a method of accessing a greater number of samples to allow greater throughput in the diagnostic analyzer. There is also a need to provide a system that will allow accurate registration of multiple sample trays.